A pilot study on 25-hydroxyvitamin D status according to sun exposure in pregnant women in Antwerp, Belgium

Vitamin D deficiency in utero or early neonatal life may have a major impact on children's health. Little is known on vitamin D deficiency in pregnant women in Belgium, non on the impact of wearing head and/or body cover.

This was a preliminary exploration of the vitamin D status in pregnant women visiting the antenatal clinic in the Antwerp University Hospital.

From August 1 2009 until November 30 2009 we systematically determined 25-hydroxy vitamin D (25-OH vitamin D) in each blood sample taken from pregnant women visiting the antenatal clinic. We also registered the degree of head/body cover and inquired for intake of vitamin supplements.

Our population consisted of 171 women, mostly primiparous, of which 86% were not covered. The mean value of 25-OH vitamin D was 28 ng/ml. Non-covered women had a mean of 29,5 ± 12,2 (SD) ng/ml, the partially covered group had a mean of 17,2 ± 7,2 (SD) ng/ml and the completely covered group had a mean of 22,5 ± 12,9 (SD) ng/ml. The difference in serum concentrations between the 3 groups was statistically significant (Anova, p < 0,00001). There were significantly more covered than non-covered women with a vitamin D concentration lower than 30 ng/ml (OR6.2; 95% CI: 1,8-21,7; p < 0,05). There was no effect of gestational age, maternal age, gravidity, parity and intake of supplements on vitamin D levels. There was a siginificant seasonal effect from summer to fall, with Vitamine D levels lowering from August to November (linear regression, p < 0,05).

Low vitamin D levels seem to be frequent and covered woman are at a higher risk of deficiency.